[GRAAP-WG] Modification to the wiki Page on Renegotiating an established Agreement
karlcz at univa.com
Fri Aug 24 07:57:26 CDT 2007
On Aug 24, Michael Parkin modulated:
> Hi Karl,
> Sorry, I have a couple of quick questions/observations... Apologies
> in advance if I have misunderstood anything in your email as
> sometimes happens.
> On 24 Aug 2007, at 11:54, Karl Czajkowski wrote:
> >... However, due to the non-binding nature of
> >these signals and the assumption of bounded rationality (we can ignore
> >the possibility of bluffing and other psychological strategies), I am
> >not sure these differences are significant. For privacy, one could
> >imagine secure advertisement channels (with authorization) to further
> >blur the boundaries.
> Are you saying that 'bluffing and other psychological strategies' can
> be ignored in the negotiation protocol that is used or in the
> negotiation strategy of each participant? For me, these two aspects
> of reaching agreement are orthogonal, just like they are in (for
> example) contract law.
I am saying that we were not considering such strategies as relevant
and therefore did not care to have multi-round negotiation to try to
support them. It was assumed that someone who did care about these
might propose further specifications that might reuse some of the
agreement data models from WS-Agreement.
> So far you have the messages: offer, advert, cancel, accept and
> reject... all of which are clear to me.
> But can you explain what the 'offers claiming agreement' step (3a)
> is? I'm sorry, I don't understand what this means - is it an offer,
> accept or another message being sent from the initiator to the
We have always assumed a notion of chaining agreements, e.g. part of
the context of an agreement could be another agreement. In the fully
agreement-based advance reservation case, the idiom is that you first
get an 'advance reservation' agreement and you then follow it up with
one or more 'claiming' agreements. The claiming agreement binds the
reservation of resource capabilities to a particular use. There are
other usage scenarios where the claiming/binding occurs in other
domain-specific protocols instead of via claiming agreements.
So it is another offer, with agreement terms which reference the
existing reservation agreement. It is implicitly understood that the
reservation agreement gives you the "right" to make these claims,
subject to the finite capacity limits of the reservation. In essence,
the entire reserve+claim process is the 2PC protocol for the actual
domain specific agreement on the consumption of resources.
You might note, this does imply a general form of multi-round
negotiation, if you were to construct domain-specific terms which
could refine or augment an existing agreement with more
information. Once you had an agreement which could claim on an
existing agreement and add more agreeable terms, you could converge
towards the point of maximum/optimal agreement, starting with more
conservative terms... however, no effort has been put into formalizing
such term languages, outside the conventional advance reservation
models we inherited into this work.
> >p.s. I will add that the fundamental challenge I see for GRAAP-WG and
> >WS-Agreement is that everyone approaches it with the same natural (but
> >incorrect) intuitions about trust, signalling, and consensus.
> Can you explain some more about what you think these shared (but
> incorrect) intuitions are?
> My intuition is to a) trust no-one, b) assume messages ('signals')
> can be lost, duplicated and re-ordered and c) assume that consensus
> may or not be reached - it depends :-). Are these the same as yours
> and/or GRAAP-WG's?
You're ahead of the game, I'd say. :-)
The typical intuition people have is that consensus can be reached
easily, discounting the byzantine faults of the Internet environment,
and having a naive understanding of what agreement and commitment
really mean. I have lost track of the number of times people have
wanted to jump into the most elaborate negotiation strategies they've
ever witnessed in real life, without considering:
1. The messaging (un)reliability model you mention.
2. The difference between intelligent and machine agents in terms
of their ability to reason and game one another.
3. The difference between contracts signed by legally responsible
entities and the automatic decisions of machines.
4. The realities of over-subscription and risk balancing in
realistic economic environments (e.g. dealing in real numbered
costs and benefits instead of hard absolutes).
5. The desired/expected/acceptable behavior for a large-scale system
with many of their proposed agents functioning simultaneously.
What I see is that people who focus on this area intensely will all
eventually start to see the same general solutions, but these are not
very compatible with what the naive user wants. So real deployment
faces the challenge of users who do not appreciate the value of these
systems nor the theoretical impossibility of what they desire.
1001 Warrenville Road, Suite 550
Lisle, IL 60532
karlcz at univa.com
The Leaders of Open Source Cluster and Grid Software
More information about the graap-wg